Rotary pressing apparatus



Feb. 12, 1924."

R. E. WAGNER ROTARY PRESSING APPARATUS Filed Feb. 14, 192i 2 Sheets-Sheet 1 r m m I.

Feb 12 ,1924; 1,483,562 R. E. WAGNER ROTARY PRESSING APPARATUS Filed e 1 1921 2 Sheets-Sheet 2 Even/0r:

Ruoom tn N57 WAGNER siding at Sweden, have invented a new and useful Im- Patented Feb. 12, 1924.

UNITED STATES PATENT ol-FicE.'

RUDOLF ERNST WAGNER, or KARLSTAD, SWEDEN,

MEKANISKA. VERKSTAD, or KARLSTAD, SWEDEN,

KARLSTAIDS ING COMPANY OF SWEDEN.

ASSIGNOR IO AKTIEBOLLGET A MANUFACTUR- ROTARY PRESSING APPARATUS.

Application filed February 14, 1921. Serial No. 444,818.

To all whom it mag comer.

Be it known that I, Rononr ERNST WAG- NER, a subject of the King of Sweden, re- Karlstad, in the Kingdom of provement in Rotary Pressing Apparatus, (for which application for patent has been filed in Sweden Feb. 25, 1920, No. 903 of 1920), of which the following is a specification.

The present invention relates to an improvement in rotary pressing apparatus for pressing out liquid from fibrous substances. It is a well known fact that if the pressing apparatus is provided with smooth cylindrical rollers, the liquid pressed out from the sheet of material run between the rollers, will principally collectin front of the rollers, with the result that particularly the liquid pressed out in this manner on the upper side of the sheet of material will increase the percentage of liquid in said sheet in such manner that said percentage may finally become too large for rendering it possible to run the sheet of material between the rollers, but said sheet will be crushed and broken. The removal in an efficient manner of the liquid pressed out in front of the rollers has there'- fore been avery important 'desideratum, and various different attempts to realize the same have been made. In order simultaneousl to increase the pressing out of the liquid and to facilitate the removal of the same it provide the rollers with grooves, notches or the like in their surfaces and extending around the rollers," to which rooves or the like the liquid shall be force to be removed in this manner. It has been found, however, that the material pressed in the pressing apparatus willag'ain absorb a portion of the liquid pressed out from the material at the point between the rollers where they are closest to one another due to the fact that the material may of course again expand as soon as it has passed said point, and can thus again absorb a portion of the liquid in the grooves or slots on either side or on both sides of the material. In orderhas been proposed, for instance, to-

ing to other constructions are wholly. or partly replaced by radial apertures orthe like in the roller, in communication with a suction devlce acting on said grooves, slots or apertures at the pressingeplace, by which term is meant the space tween the tions of the circumferences of'the -ro lers which act on and press together the material run between the rollers. It has been found,

however, that it is not possible in this manner to attain a satisfactory removal of the liquid in the grooves, slots or apertures, the probable explanation of which fact is that at the point where the material is most firmly pressed together no air can be drawn a through the material into and through, and bring along the liquid in, the apertures or portions of the grooves or slots contacting with. the material at saidplace.

According to the present invention, however, the. difliculties above. referred to are avoided and a perfectly satisfactory removal of the liquid ressed out from the sheet of material is obtained by the use of rollers provided with circumferential slots or grooves, in combination with suction means arranged adjacent the rolling surface of one roller or each roller and projecting into the angle between said surface and the sheet of material run between the rollers, said suction means being adapted to draw off the liquid which is pressed out from the sheet of material into said slots or the like and which would tend to flow from these'slots out into the angle-or angles between the sheet of material and the surface of the roller. Bythis combination there is attained, not only satisfactory drawing off of the looting in front of the rollers, but also a complete drawing off of the liquid farthest into said angles and the liquid forced into the slots, due to the fact that air will be drawn from one side of the rollers through the slots to the suction device on the other side of the rollers, and will thereby bring along all the liquid in the slots as Well as the liquid farthest into the angles, said liquid will -be thoroughly removed and can not be reabsorbed by the sheet of material.

The accompanying drawings illustrate diagrammatically and by way of example a liquid colso that few embodiments of the present invention. Fig. 1 is adiagrammatic view of a pressing apparatus for cellulose or wood pulp. Fig. 2 shows to a larger scale an embodiment which may be one of the presses in Fig. 1. Fig. 3 shows an embodiment in which the sheet of material is run vertically between the rollers from below upwards. Fig. 4 shows the invention applied to a pulp-vat. Fig. 5 shows diagrammatically a face view of a slotted roller.-

Referring to Fig. 1, 1 denotes the usual wire part with the wire 2 which runs, and moves the sheet of material, through the couch press 3. In front of the upper roller 4 of said press viewed in the direction of movement of the sheet of material, and in the angle between the surface of the roller and the sheet of material on the wire 2 there is provided a suction means 5 for drawing off the water pressed out from the sheet of material in front of the roller 4. A felt 6 is placed around the roller 4 and the suction means 5 and runs over suitable guiding means, it having been found that when the sheet of material contains a large percentage of liquid, said sheet should preferably not come into contact with the stationary suction means 5 because rolls will then easily be formed on the surface of the sheet which is of course very disadvantageous. The roller 4 is provided with narrow and comparatively deep slots extending around the same. The liquid will be pressed from the sheet of material through the felt and into the slots and in front of the roller, and the suction means 5 will draw ofl the liquid in front of the roller 4 as well as the liquid in the slots.

7 indicates the so-called first press to which the sheet of material is led from the couch press. As indicated in the drawing, there is provided for the upper roller 8 a suction means 9 and a felt 10 in similar manner as for the couch press 3. The roller 8 is provided with slots. The lower roll-- er 11 may also be provided with slots, or be smooth, and there may also be provided for the same a suction means 12 and a felt 13 one or both of which may be omitted, however, and they are therefore shown with dotted lines in the drawing. From said first press 7 the sheet of material is led in.- to the second press 14. In said second press the upper roller 15 and referably also the lower roller 16 are provi ed'with slots, and a suction means 17 is provided for the upper roller, but no felt isas a rule required for this second press owing to the fact that when introduced into the same the sheet of material holds such large percentage of dry matter that it will not become damaged if it touches the suction means 17.

, It has been found that the advantages obwt... by the described arrangement are very great. It is well known that the sheet of material in a machine for drying cellulose holds at the point A, that is to say when the material is introduced into the couch press, as a rule 10 to 12 per cent of dry matter. In machines as hitherto used the sheet of material, when discharged from the couch press at the point B, holds as a rule only 15 to 18 percent of dry matter, whereas by means of the present improvement a considerably larger percentage of dry matter is obtained at said point. At the point C, where the sheet of material is discharged from the first press, if .said press is arranged in the manner heretofore used, that is to say with smooth rollers and felts, only 30 to 32 percent of dry matter has been obtained, whereas by means of the present improvement 40 to 41 per cent of dry matter is obtained. In order to obtain a percentage even approximately comparable to the last mentioned one, it has thus hitherto been necessary to use two presses one after the other. It is true that by heating the sheet of material leaving the couch press to about 40 C. it is possible to attain 35 per cent of dry matter already in the first one of said two presses, but in such case it has not been possible with the second press to obtain more than 2 or 3 additional percent, and the total percentage-has thus become 37 or 38. It is thus obvious that by means of the so-called first press 7 in Fig. 1, a better result is obtained than with two presses of the construction hitherto used. IVith the second press shown in Fig. 1 approximately 50 per cent absolutely dry pulp is obtained at the point D. The further advantage is also obtained, that owing to the increased pressing out of liquid in the couch press, it is possible to work with a thicker sheet of material with the same speed of the machine, an increased production thus being attained.

Fig. 2 shows to a larger scale the ress 7 in Fig. 1. The rollers S and 11 which are shown diagrammatically in face view in Fig. 5 are provided with circumferential slots, and the suction means 9 and 12 bear against said rollers, while the felts 10 and 13 run around said rollers, and suction means. These latter means consist of boxes connected to suitable suction conduits, one edge of each of said boxes projecting into the angle between the corresponding roller and felt, and the other edge of said means bearing against the surface of the roller and being tightened against said surface in suitable manner. So-called scrapers 18 may be inserted in the slots in order to increase the tightness. The figure illus trates the drawing off of the water pressed out.

Fig. 3 difieres from the arrangement according to Fig. 2 substantially only'in that the sheet of material passes between the rollers from below upwards.

Fig. 4 shows a pulp-vat in which the loWer roller 25 'is a strainer or suction roller and forms in the usual manner one wall of the pulp receptacle 26. The upper roller 27 is provided with slots, and the suction box 28 cooperates with said roller. The felt 29 runs around the roller 27 and the suction box 28.

I claim:

1. In a rotary pressing apparatus for pressing out liquid from fibrous substances, the combination of two press rollers adapted to press against a sheet of material run between the same, at least one of said rollers being provided with circumferential slots in its surface, and a suction device located in front of such slotted roller in the angle formed between its surface and the sheet of material and adapted to draw off liquid pressed out from the sheet of materialinto said angle in front of the roller and into the slots in the roller.

2. In a rotary pressing apparatus for pressing out liquid from fibrous substances, the combination of two press rollers adapted to press against a sheet of material run between the same, at least one of said rollers being provided with circumferential slots in its surface, and a suction device located adjacent such slotted roller in one of the angles formed between its surface and the sheet of material and adapted to draw ofi' liquid pressed out from the sheet of material into the' slots in the roller.

3. In a rotary pressing apparatus for pressing out liquid from fibrous substances, the combination of two press rollers adapted to press against a sheet of materialrun between the same, at least one of said rollers being provided with circumferential slots in its surface, a felt running over said slotted roller, and a suction device located adjacent such slotted roller in an angle formed between its surface and said felt and adapted to draw off liquid pressed out from the sheet of material through said felt into the slots in the roller.

RUDOLF ERNST WAGNER. 

